1. Field of the Invention
The present invention relates to a multi-loop antenna, especially to the antenna with two or more slices of conductors that connect with two or more antenna units that receiving signals of different frequencies, and thus achieving good capacity in receiving multiband frequency and/or broadband frequency.
2. Description of the Prior Art
The structure of an internal antenna in a mobile phone in prior art shown in FIGS. 1A and 1B. On top of the FIG. 1A is the antenna substrate 200, and the grounding substrate 100 is beneath the antenna substrate 200. The aforementioned substrates are connected by a component 300. In general, as shown in FIG. 1B, the distance between the antenna substrate 200 and the grounding substrate 100 is extended in order to increase the bandwidth of the frequency. The longer the distance xe2x80x9cdxe2x80x9d is, the lower the equivalent value Q is, meanwhile, the frequency bandwidth of the signals is increased.
However, the thickness of a conventional mobile phone is limited, so the distance between the antenna substrate and the grounding substrate is restricted. Therefore, an idea of multi-loop structure of antenna circuit is invented to produce diverse combinations in neighboring antenna units in order to receive multi frequency. By the means of the multi-loop design, the antenna may receive frequency with multiband resonance.
A present structure of a conventional antenna is shown in FIGS. 2A and 2B. It is clearly shown that the present structure, which is on the antenna substrate 200, comprising two antenna units 4a and 4b. Wherein, a longband antenna 4a is located in the outside of the antenna substrate 200 and connects to the grounding end, and a shortband antenna 4b is located in the inside of the antenna substrate 200, connecting the feeding end. There is a conductor 4c mounted between the longband 4a and the shortband 4a. A current 900 may enter the feeding end, passing through shortband 4a, connecting conductor 4c and longband 4b, and then to the grounding end. Thus a complete circuit is formed.
In this type of sliced antenna in mobile phones, the position and the amount of the conductors 4c is fixed. Therefore, it can just form only one circuit and receive dual-band frequency.
Moreover, as the circuit of this type of antenna is fixed, the received dual frequency is also fixed. As a result, the frequency ratio cannot be tuned.
Accordingly, it is an object of the present invention to provide a multi-loop antenna, which increases the frequency bandwidth by means of the antenna units receiving different frequencies and being connected together. It is another object of the present invention to enable the adjustment of the proportion of the wideband/multiband frequencies by means of the antenna units connected by two or more conductors, wherein the antenna units, which receive different ranges of signals. According to the multi-loop antenna of the present invention, by means of two or more connecting conductors, different modules of connections may be accomplished, and the ability and flexibility of receiving wideband signals may also be achieved, and thus the frequency ratio and the flexibility of signal receiving are increased. It is a further object of the present invention.
The present invention will be better understood and its numerous objects and advantages will become apparent to those skilled in the art by referencing to the following drawings in which: